Apparatus for enhancing draft through furnace-fires.



A N0.74s,e94. 'PATENTED NOV. 10, 1903.

A s. 0. DAVIDSON.

APPARATUS FOR ENHANCING DRAFT THROUGH FURNACE FIRES.

APPLICATION-FILED APR. 29,1603.

no menu. s sums-sum 1.

, INVENTQR I WITNESSES: w v By Altomeys, A A..-

No.743,69-.4. PATENTED N0v.10,190s.

s. 0. DAVIDSON. APPARATUS FOR ENHANOING DRAFT THROUGH FURNACE FIRES.

APPLICATION FILED APRh ZQ, 1903. K0 MODEL. 3 SHEETS-SHEET 2,

Z Z 74 41 why;

THE mums PETpiSjEDT-PN PATENTED NOV. 10, 1903.

s. 0. DAVIDSON. APPARATUS FOR ENHANCING DRAFT THROUGH FURNACE FIRES.

APPLICATION I'I LED APR. 29, 1903.

3 SHEETS-SHEET a.

N0 MODEL.

'INVENTQR:

, By Altameys,

WITNESSES:

rm: NoRRls PETERS CO,PHOTD-LITHO.. vusumcwou, o, by

, iq.74;3,6t4. e I v p TED STATE Patented November 1Q, 1903.

PATENT ()FFICE.

S MUEL c EL nD nAvlpson, OF BELFAST, IRELAND.

APPARATUS EOREENHANCING DRAFT THROUGH FURNACE-FIRES.-

srscmxoerro'nfomin part'of Letters Patent No. 743,694, dated November 10, 1903.

Application filec l April 29. 1903.

To all whom, it mag concern: l 1 Be it known that I, SAMUEL CLELAND DA- VIDSON, merchant,- of Sirocco EngineeringlVorks, Belfast, Ireland, have invented cer- 'tain new and useful Improvements in Apparatus for Enhancing Draft-Through Furnace- Fires,of which the following isaspecification. My improvements relate more particularly to apparatus for enhancing draft through the furnace-fires of land and marine boilers and of railway or road locomotives or tractionengines, (hereinafterreferred to as loc'omotives;) and the objects of my invention are "to provide improvedapparatus for producing by mechanical meansa strong-and effective draft through said furnace-fireswith a minimum, absorption of power for the operation of same, while also providingj'or the alter: native employment when requiredof what is" termed the natural draft ofthe chimney or funnel connected theretowithout involving the employment of damper-valves when changing over from natural to mechanical draft, or vice versa. l

Chimneys of moderate height-say up to' eighty feet, or thereabout, above the "firegrate -donot develop suff cient strength of draft to produce in said fires a'combnstion of the requisite intensity to efiectively consume common and low priced qualities of coal, which if burned with a strong draft give 01? more heat and develop-more steam relativelyto cost than high-priced qualities. Oonsequently a strong draft on thefires is a very important factor toward economy in cost for fuel. it v According to my invention, the novel features of which are specially defined in the claims at the end of this specification, th'fiffan is placed bodily within the flue'and practically" forms a constituent practically so arranged and of such dimensions as to practically provide a through-passage of. crosssectional area equal toth'at of the flue or of at least one-sixth of "the surface area of the fire grate being operated upon by said fan.

partthereof, and Idivide i the flue into. passages or chambers, one or more'of which are. adapted to contain a fan. or fans, while the others form conducting passages or chambers to the fan and through same to the flue beyond, said passages being a Serial in. 154,771," (No model.)

reference to the accompanying drawings,

application to several Twill further describe my'invention with q Figures l'and 2'are respectively afront sectional elevation and a side elevation showing the application of my invention on the 1 top of a land-boiler of the water-tube type, only thefsteam-drum and the upper'part of the boiler being'shown in full. Fig. 3 shows in sectional elevation an arrangementof my invention applied to the fines ofv steamship boilers. Figs; 4, 5-, and 6 show anarrangement of my invention applied to the smoke box of a locomotive or traction-engine.

Fig.

4 is a sectional side elevationgiand Fig. 5, a a

side elevation of Fig. 6,'which isasectional shown applied tothe top of a land-boiler ot i the water-tube type, the uptake from the elevation showing the front of the boiler.

; In Figs. 1 and'2, where the invention is boilerflues is here elongated to form side fluesb b on each side .of the steam-drum and having walls h h between them and thesteamdrum, althoughthe sides of the steam-drum may in some cases form part of the. inner walls. The said ilues b b com'municate'with .the inlets e e to a fan-chamber c, whichis located-on the top of the steam d rum. The products of combustion pass through said side flues into the fan through the opening's'e e and are discharged therefrom from the fanchamber upwardlyinto the base of a chimney or funnel t. through the outer walls of the fines b b and mounted'in bearings fixed on suitable pedestals, oif:jbrackets, such as k k. ing the-shaft there maybe openings in the outerwallsof the. fines of-snflicient size to allow offithe removal of the fan the reth rough,

Surround The fan-shaftis extended.

abie'det lates or coversa u. Apart fnpmtth special features, the-general operation his arrangement is similar, to that describe'dinrespect of-Figs, land 2; and

the ame' letters of, preferen indicate Spending pa -f p 7 'It will be obvious thatgaslthe a! side fines. jointhe continuation ofith mar flue, and. thereby terminate said side; flueskv l the products of combustion passi'ng throin'gh the'same from the main flue must necessaril will take place, as hereinafter more partied-- larly described.

When necessary, the three chambers combined may be of somewhat greater width than the main flue, so as to provide in said bifurcated suction-fines a united cross-sectional area of passage-way equivalent to preferably not less than one-sixth of the area of the firegrate being dealt with, and the inlet-openings tothe fan and also the discharge-outlet therefrom into the continuation of the main fine to the chimney or funnel should preferably, also, haveat least the same area for passage-way of the gases in order that when the fan is not being rotated and merely the natural draft of the chimney or funnel is operative the gases will have a sufficiently free passage to the chimney or funnel to enable said natural draft to maintain approximately the ordinary cfiective rate of combustion which the chimney or funnel can of itself develop in the furnace-fires, so that on the fan being rotated an acceleration of this draft will'take place, the-strength of which on the fires will then be commensurate with the speed of the fans rotation.

In Fig. 3, which shows the application of my invention to marine boilers, the same general principle of construction is employed as above described for land-boilers, with modifications merely to suit the conditions necessarily pertaining to boilers in steamships. The uptake or smoke-duct from marine boilers to the 'funnel may be taken as substantiallythe equivalentof the main flue of landboilers, and between the upper end of same and the base of the funnel I construct my hereinbefore-described fan-chamber and side c'ham bers, forming the three divisional compartments therein, as already set forth. In this modification the fan-chamber c practically forms a basement-chamber underneath the chimney or funnel t, the suction or side fiues b b being substantially a continuation the tangential discharge of the gases from the fan being as nearly as practicable parallel or coincident with the axis of the funnel. The

scribed, and similar letters of reference indicate corresponding parts.

In applying my invention to locomotives, as shown in Figs. 4, 5, and 6, the ordinarilyemployed smoke-collecting chamber at the funnel end of the boiler (which is usually known and hereinafter referred to as the smoke-box) may likewise be regarded as equivalent to the main fine in land-boilers. H is the smoke-box, the sides h h of which are elongated upwardly to form the fan-chamber,com prising the central chamber 0 and side fines b b, communicating with the inlets e e of the centrally-located centrifugal fan din the chamber 0, the discharge from which ,is directed upwardly into the base of thefun: nel t, which practically constitutes an elongation of the fan-discharge nozzle. The inlets e e in the fan-casing c are of sufficient diameteigto admit of the insertion or with" drawal of the fan 61 through same, and cor spondin'g orifices are provided in the walls of the fines b b, which orifices'when thefan is in position are closed by disks u 21.,containing a central orifice through which the fan- I shaftj passes, said shaft being carried in bearings 7t 75', attached to the outer sides of said 1 fines of.landboilers or the uptake from marine boilers or smoke-box of locomotives or traction-engines, the essential features of my invention being as hereinafter claimed.

The fan-casing where it extends out,

The accompanying drawings merely serve to illustrate convenient forms of application which would'be subject to modification to suit the particular circumstances or practical requirements of each individual installation.

In my above-described apparatus; whether" same beemployed in connection with land or marine or locomotive boilers, the fans may be driven by any suitable form of motor either direct couplednt herewith or driving same by a belt or chain, and Imay employ fans of either centrifugal or propeller types. When the centrifugaltype is employedQI- preferably employ fans of, thety ie described in the specification of previous letters Pat'- ent granted to me and dated November 27,

1900, and n'umbered'662, 395, asv these fans have important advantages'in. thiscombination, in that theyoccupyavery small space relatively to the volume of' gases they can deal with and im part to the gasesa very high velocity relatively to their speedofirotation, and I preferably use said fans of the type known as the double-inlet construction, in which the vanes or blades are mounted on each side of a central disk, which keeps the currents,offgasbsient e through into oneanothei' ibut'when l employ the pro I ,v mou nt onein each inletopening tovthe-fag-casing. f

peller-fan which I preferably employ is that described and shown in thespecification of previous Letters Patent granted to me and datedJuly 22', 1902, and

numbered 705,046, as they likewise have the -importantadvantagesof occupying a very small space relatively to-the volume, of gases dealt with and impart to the gases a higher velocity relatively totheir speed of rotation than square of the enhanced is the case withfpropeller-fans of other makes, and the construction and special curvature of the blades enable them to stand very high temperatures-without warping or twisting.

In all the above modifications the strength of the draft forvarying requirements is completely under control, and a much stronger draft-power can be obtained by means of my herein-described improved apparatus than would be practicable within the limits of height which necessarily apply to the funnels of locomotives or steamships and in many cases to land-boilers. The introduction of the fan-casing bodily, as it were, into the main flue, as hereinbefore described, permits of the gases entering same with a minimum of deviation from the direction of their flow through the main flue and facilitates the maintenanceof large passage-ways for the gases into and through the fan, so that the velocity'of flow through same is approximately the same as through the main flue itself, so that not only can the gases pass through the fan freely under natural draft when the fan is not rotated, but when the fan is rotated receive therefrom an accelerated .velocity with a minimum expenditure of power, there being no unduly greatervelocity of flow through the fan than issimul taneously set up in the main flue, whereby a veryimportant economy of power is effected, because when the gases have to be forced through passages of any considerably-contracted area relatively to that of the main flue through which they are drawn and dis-r charged the power required to produce this acceleration on a' given volume rises as the velocity applied thereto,

' invention obviates necessity for the use of contracted passages the required duties are.

consequently obtained with alminimum of power for the effective draft created on the} ated ginletsifrom impinging.

and as my hereinbefore:described invention to steamships can be efiected in what is usually an unoccupied space above the boilers without interfering with other appliances in the very confined space around and over the boilers-a matter of much practical importance as regards apparatus which has to be located in stoke-holds.

i What I claim as my invention, and desire to secure by Letters Patent, is

l 1. In an apparatus for enhancing draft through furnace-fires, the combination of a bifurcated flue, a fan-chamber, a fan mount-, ed in said chamber so as to discharge into the chimney or funnel, oppositely-located inlets into said fan-chamber, from the bifurcations of said line and forminga continuation of the bifurcated flue through the fan-chamber to the chimney or funnel beyond, and a central partition which keeps the currents of gases entering the fan through its oppositelylocated inlets from impinging upon one another.

2. In an apparatus for enhancing draft through furnace-fires as applied to an up-' weirdly-directed flue as in marine and locomotive boilers or the top of land-boilers, the combination of a central fan-chamber formed at or near the base of the chimney or funnel and closed at its base, a fan mounted in said chamber so as to discharge into said funnel, a bifurcated uptake forming flues at the side of said chamber, inletsat the side of the central chamber and forming a continuation of the bifurcated uptake through the fan-chamber to the flue beyond,said fan being of the centrifugal type with a central disk which keeps the currents of gases entering the fan through its oppositelydocated inlets from impinging upon one another, and means for driving said fan.

3. In an'apparatus for enhancing draft through furnace-fires as applied to an upwardly-d'irectedfiue as in marine and locomotive boilers or the top of'land-boilers, the combination of a central fan-chamber formed at the base of the funnel and closed at its base, a fan mounted in said chamber so as to discharge into said funnel, a bifurcated uptake forming lines at the side of said-ecu;

ITO

tral chamber, inlets in the side of saidc'en I tral chamber and forming a continuation of the bifurcated ,uptake'through the central chamber to the fl-ue beyond, the outer wall of the uptake having an aperture in line with the fan-axis and of sufilcient diameter to'ad-v mit the insertion or withdrawal of the fan through the same, a detachable'plate for clos ing said aperture, means for driving said fan, and a'central partition which keeps the currents of gasesfentering the fan through its oppositelylocated inlets from impinging upon one anothen. j' a a V 4. In apparatus for enhancing draft through" furnace-tires as applied to an upwardly-directed fiueas in marine and locomotive boil-,

are or the top of land-boilers, the combination of a central fan-chamber formed at the gases entering the fan through its oppositelylooated inlets from impiugingnpon one another.

'In witness whereof I have hereunto signed iny name in the presence of two subscribing witnesses.

SAMUEL CLELriND DAVIDSON.

Witnesses:

GEORGE-F. WARD, WM. FREW. 

